Diagnosis of pelvic endometriosis by magnetic resonance imaging using "fat-saturation" technique

Abstract

Objective: To assess the usefulness of fat-saturated magnetic resonance (MR) imaging for detecting small endometrial implants.

Design: Prospective evaluation by conventional and fat-saturated MR imaging.

Setting: Shimane Medical University Hospital, Izumo, Japan.

Patients: Fifty-one consecutive patients with clinically suspected pelvic endometriosis.

Interventions: Magnetic resonance images < 2 weeks before laparoscopy or laparotomy.

Main outcome measure: The location, number, and size of lesions.

Results: Surgery revealed a normal pelvis in 5 patients, endometriosis in 44 (42 with pigmented lesions and 2 with nonpigmented lesions and adhesions), and other cystic lesions in 2. With fat-saturated MR imaging, overall sensitivity, specificity, positive predictive value, and negative predictive value were 89%, 71%, 95%, and 50%, respectively. At surgery, 122 pigmented lesions of endometriosis were detected. Conventional MR images indicated lesions of endometriosis in 74. When fat-saturated images were used, 103 lesions were detected. With conventional MR images, only one of 34 small endometrial implants (2 to 3 mm in diameter) was detected. However, the addition of fat-saturated images increased the detection rate to 15 of 34, and all lesions > 4 mm in diameter.

Conclusion: Conventional MR imaging for detecting small endometrial implants was improved by addition of the fat-saturation technique. Therefore, fat-saturation MR imaging is an acceptable for detecting small endometriomas.